1. Field of the Invention
The present invention relates to a voltage divider circuit, which divides an input voltage in accordance with a predetermined ratio to output the divided voltages.
2. Description of the Related Art
Conventionally, there has been used a voltage divider circuit, which divides, in accordance with a set ratio, an input voltage into predetermined voltages to be used in an internal circuit or the like.
As the voltage divider circuit, in order to generate an accurate potential difference, there is generally used a resistive voltage divider circuit, in which resistors (for example, 500, 501, and 502) are connected in series as illustrated in FIG. 3, for dividing a voltage input from a voltage source or a signal source in accordance with a ratio of resistance values thereof, and for outputting the divided voltages. There have been proposed various circuit configurations (for example, see JP 02-250514 A).
However, the resistive voltage divider circuit is configured by connecting the resistors in series between the input signal source and a ground point. Accordingly, power is consumed for the dividing of voltage.
Moreover, in the case where the voltage divided by the resistive voltage divider circuit is supplied to a load circuit which uses this voltage, when a source current fed from the load circuit or a sink current fed to the load circuit is generated, a voltage drop occurs in a voltage divider resistor, and a resistance ratio of the divided voltages is changed in an equivalent manner, whereby a divided voltage value cannot be obtained accurately.
For this reason, the resistive voltage divider circuit is incapable of dividing a voltage with high accuracy in the case of high impedance at which the input signal source cannot supply power or the case where a load current needs to be supplied from the voltage divider circuit.